- Snow blindness
Name = PAGENAME
DiseasesDB = 31147
ICD10 = ICD10|H|16|1|h|15
ICD9 = ICD9|370.24
eMedicineSubj = emerg
eMedicineTopic = 759
Snow blindness (Niphablepsia) is a painful condition, typically a
keratitis, caused by exposure of unprotected eyes to the ultraviolet(UV) rays in bright sunlightreflected from snowor ice. This is especially a problem in polar regionsand at high altitudes, as with every thousand feet (approximately 305 meters) increase in elevation, the intensity of UV raysgoes up five percent.
The problem is also related to the condition
arc eyesometimes experienced by welders.
Snow blindness is akin to a
sunburnof the corneaand conjunctiva, and may not be noticed for several hours from exposure. Symptoms can run the gamut from eyes being bloodshot and teary to increased pain, feeling gritty and swelling shut. In very severe cases, snow blindness can cause permanent vision loss.
Inuitcarved gogglesfrom caribou antlerto help prevent snow blindness. The goggles were curved to fit the user's face and had a large groove cut in the back to allow for the nose. A long thin slit was cut through the goggles to allow in a small amount of light. The goggles were held to the head by a cord made of caribou sinew.
trekking, mountaineeringor skiing, sunglassesthat offer the following are frequently recommended:
* 99-100% UV absorption
Polycarbonateor CR-39 lens
* 5-10% visible light transmittance
* Large lenses that fit close to the face and cover the whole eye
* Wraparound, side-shielded, or dark-lensed 'glacier'
glassesto prevent incidental light exposure
* Wear even when the sky is overcast, as
UV rayscan still filter through clouds
* In the event of lost or damaged sunglasses, make emergency
gogglesby cutting slits in dark fabric or tape folded back onto itself
Following these guidelines will allow the pain and symptoms of snow blindness to disappear as the
* Avoid rubbing eyes and remove
* Administer an oral pain medication such as
* Cover eyes with soft thick cloth pads or
gauzebandages to prevent irritation from eyelid movement and protect from light; rest in a dark room if possible
* Apply cold wet compresses to ease burning sensations
* Check injury at half-day intervals; remove dressing when eyes can remain open comfortably
sunglassesoutside until symptoms completely disappear
* [http://www.basecampmd.com/expguide/snowblind.shtml Everest Base Camp Clinic - Eye Concerns at Altitude]
* [http://www.mounteverest.net/expguide/snowblind.htm Mount Everest.net - Snow Blindness]
* [http://www.gpnotebook.co.uk/cache/-268042203.htm General Practice Notebook - Snow Blindness]
* [http://www.sherpatrek.com/pemas_stories/pemas-snow-blind.php An Experience of Snow Blindness]
* [http://www.athropolis.com/arctic-facts/fact-goggles.htm Historical Snow Goggles]
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